The vacuum nitrided stop square with its height of 800 mm and its wear-free tight surface is designed for heavy claimed application and ensures protection from corrosion and a long lifetime. Moreover, the plasmanitriding is one of the most ecological hardening processes as only nitrogen, hydrogen and oxygen are used. It is used in welding and clamping technics for accurately defined positioning and fixing of working parts. The strained bar mortises powerful against the working piece and visualizes strength. Cavities at the whole square decrease the weight to 28,5 kg and therefore improve the daily handling.